Abnormal gene expression during early placental development has been associated with adverse pregnancy outcomes. However, the transcriptional regulatory networks underlying normal placental development, includ- ing the transcription factors, the enhancers they bind to, and the genes they regulate, are unknown. Until this fundamentalgapisfilled,thevariantsingenomicDNAthatcauseaberrantgeneexpressionandleadtopreg- nancycomplicationscannotbeunderstood.Theapplicant?slong-termgoalistoidentifyglobalmechanismsby whichtranscriptionfactorsandenhancersworktogethertoregulateplacentaldevelopment.Theoverallobjec- tiveofthisapplicationistodefineandcharacterizetranscriptionalregulatorynetworksforprocessesthatoccur duringthreecriticaltimepointsofmouseplacentaldevelopment(embryonicdays7.5,8.5,and9.5),priortothe formationofthematureplacenta.Thecentralhypothesis,basedonpublishedandpreliminarydata,isthattime point-specific transcriptional regulatory networks regulate distinct processes during early placental develop- ment, and that disruption of transcription factors or enhancers central to these networks leads to abnormal trophoblastgeneexpression.Therationalefortheproposedresearchisthatunderstandingtheregulatorynet- worksunderlyingearlyplacentaldevelopmentwillenableearlydetectionandtreatmentofplacentaldisorders. The central hypothesis will be tested using three specific aims: (1) to define process-specific transcriptional regulatory networks during early placental development;? (2) to determine the mechanisms by which key TF- enhancerpairsregulategeneexpressioninmousetrophoblastsubtypes;?and(3)todeterminetherelationship between cis-regulation in mouse and human trophoblasts. To execute these aims, we will use an integrated approach, combining experimental genomics (RNA-Seq, ChIP-Seq, and ATAC-Seq), computational analysis (e.g. co-expression analysis, enhancer module analysis, and binding site predictions), and functional assays (e.g.ChIP,reporterassays,andsiRNAknockdown).Eachaimissupportedbyastrongscientificpremiseand preliminarydata,andeachmethodhasbeenestablishedeitherintheapplicant?slaborinthelabofamember of the research team. Completion of this project willresult in a global understanding ofthe transcriptional net- works regulating early placental development, and in an understanding of the mechanisms by which key TF- enhancerpairsregulategeneexpressioninmouseandhumantrophoblastcells.Theresearchproposedinthis application is innovative, in the applicant?s opinion, because it represents a new and substantive departure from the status quo by shifting focus to genome-scale identification and characterization of TF-enhancer net- worksthatregulatespecificprocessesduringplacentaldevelopment.Thiscontributionissignificantbecauseit will provide a new understanding of normal placental development, ultimately leading to the development of noveltherapeuticinterventionsforplacenta-associateddisorders.